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Nanomaterials, Volume 5, Issue 2 (June 2015), Pages 386-1135

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Editorial

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Open AccessEditorial Frontiers in Nucleic Acid Nanotechnology
Nanomaterials 2015, 5(2), 750-754; doi:10.3390/nano5020750
Received: 4 May 2015 / Accepted: 7 May 2015 / Published: 8 May 2015
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Abstract
This Special Issue of Nanomaterials highlights innovative work from around the world focused on harnessing the physical, chemical and topological properties of nucleic acids. [...] Full article
(This article belongs to the Special Issue Frontiers in Nucleic Acid Nanotechnology)

Research

Jump to: Editorial, Review, Other

Open AccessArticle Synthesis of Silver-Strontium Titanate Hybrid Nanoparticles by Sol-Gel-Hydrothermal Method
Nanomaterials 2015, 5(2), 386-397; doi:10.3390/nano5020386
Received: 4 February 2015 / Revised: 10 March 2015 / Accepted: 18 March 2015 / Published: 24 March 2015
Cited by 4 | PDF Full-text (2790 KB) | HTML Full-text | XML Full-text
Abstract
Silver (Ag) nanoparticle-loaded strontium titanate (SrTiO3) nanoparticles were attempted to be synthesized by a sol-gel-hydrothermal method. We prepared the titanium oxide precursor gels incorporated with Ag+ and Sr2+ ions with various molar ratios, and they were successfully converted into
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Silver (Ag) nanoparticle-loaded strontium titanate (SrTiO3) nanoparticles were attempted to be synthesized by a sol-gel-hydrothermal method. We prepared the titanium oxide precursor gels incorporated with Ag+ and Sr2+ ions with various molar ratios, and they were successfully converted into the Ag-SrTiO3 hybrid nanoparticles by the hydrothermal treatment at 230 °C in strontium hydroxide aqueous solutions. The morphology of the SrTiO3 nanoparticles is dendritic in the presence and absence of Ag+ ions. The precursor gels, which act as the high reactive precursor, give rise to high nucleation and growth rates under the hydrothermal conditions, and the resultant diffusion-limited aggregation phenomena facilitate the dendritic growth of SrTiO3. From the field-emission transmission electron microscope observation of these Ag-SrTiO3 hybrid nanoparticles, the Ag nanoparticles with a size of a few tens of nanometers are distributed without severe agglomeration, owing to the competitive formation reactions of Ag and SrTiO3. Full article
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Open AccessArticle Separator Membrane from Crosslinked Poly(Vinyl Alcohol) and Poly(Methyl Vinyl Ether-alt-Maleic Anhydride)
Nanomaterials 2015, 5(2), 398-414; doi:10.3390/nano5020398
Received: 6 January 2015 / Revised: 8 March 2015 / Accepted: 12 March 2015 / Published: 25 March 2015
Cited by 3 | PDF Full-text (592 KB) | HTML Full-text | XML Full-text
Abstract
In this work, we report separator membranes from crosslinking of two polymers, such as poly vinyl alcohol (PVA) with an ionic polymer poly(methyl vinyl ether-alt-maleic anhydride) (PMVE-MA). Such interpolymer-networked systems were extensively used for biomedical and desalination applications but they were not examined
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In this work, we report separator membranes from crosslinking of two polymers, such as poly vinyl alcohol (PVA) with an ionic polymer poly(methyl vinyl ether-alt-maleic anhydride) (PMVE-MA). Such interpolymer-networked systems were extensively used for biomedical and desalination applications but they were not examined for their potential use as membranes or separators for batteries. Therefore, the chemical interactions between these two polymers and the influence of such crosslinking on physicochemical properties of the membrane are systematically investigated through rheology and by critical gel point study. The hydrogen bonding and the chemical interaction between PMVE-MA and PVA resulted in highly cross-linked membranes. Effect of the molecular weight of PVA on the membrane properties was also examined. The developed membranes were extensively characterized by studying their physicochemical properties (water uptake, swelling ratio, and conductivity), thermal and electrochemical properties using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), thermo-gravimetric analysis (TGA) and electrochemical impedance spectroscopy (EIS). The DSC study shows the presence of a single Tg in the membranes indicating compatibility of the two polymers in flexible and transparent films. The membranes show good stability and ion conductivity suitable for separator applications. Full article
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Open AccessCommunication Fabrication and Cell Responsive Behavior of Macroporous PLLA/Gelatin Composite Scaffold with Hierarchical Micro-Nano Pore Structure
Nanomaterials 2015, 5(2), 415-424; doi:10.3390/nano5020415
Received: 20 November 2014 / Revised: 16 March 2015 / Accepted: 17 March 2015 / Published: 25 March 2015
Cited by 3 | PDF Full-text (485 KB) | HTML Full-text | XML Full-text
Abstract
Scaffolds providing a 3D environment which can effectively promote the adhesion, proliferation and differentiation of cells are crucial to tissue regeneration. In this study, the poly-l-lactic acid (PLLA) scaffold with hierarchical pore structural was fabricated via two-step thermally induced phase separation (TIPS). To
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Scaffolds providing a 3D environment which can effectively promote the adhesion, proliferation and differentiation of cells are crucial to tissue regeneration. In this study, the poly-l-lactic acid (PLLA) scaffold with hierarchical pore structural was fabricated via two-step thermally induced phase separation (TIPS). To mimic both physical architecture and chemical composite of natural bone extracellular matrix (ECM), gelatin fibers were introduced into the pores of PLLA scaffolds and formed 3D network structure via TIPS. Human adipose tissue-derived stem cells (ADSCs) were harvested and seeded into PLLA/gel hybrid scaffolds and cultured in vitro for biocompatibility assay. The surface morphology, porosity and compressive modulus of scaffolds were characterized by scanning electron microscopy (SEM), density analysis and compression test respectively. The results showed that hybrid scaffolds had high porosity (91.62%), a good compressive modulus (2.79 ± 0.20 MPa), nanometer fibers (diameter around 186.39~354.30 nm) and different grades of pore size from 7.41 ± 2.64 nm to 387.94 ± 102.48 nm. The scaffolds with mild hydrolysis by NaOH were modified by 1-ethyl-3-(3-dimethyl ami-nopropyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS). Gelatin was performed onto PLLA scaffold via TIPS aiming at enhancement cell-material interaction. In comparison with PLLA scaffold, the PLLA/gel scaffold had better biological performance and the mechanical properties because the gelatin fibers homogeneously distributed in each pore of PLLA scaffold and formed 3D network structure. Full article
(This article belongs to the Special Issue Frontiers in Mesoporous Nanomaterials)
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Open AccessArticle Meso-Structuring of SiCN Ceramics by Polystyrene Templates
Nanomaterials 2015, 5(2), 425-435; doi:10.3390/nano5020425
Received: 27 February 2015 / Revised: 17 March 2015 / Accepted: 19 March 2015 / Published: 27 March 2015
Cited by 9 | PDF Full-text (778 KB) | HTML Full-text | XML Full-text
Abstract
A simple one-pot synthesis of well-defined PS-silazane nano-composites (polystyrene, PS) is described. In contrast to the, thus far, used two-step procedure ((1) assembly of a PS template bed and (2) careful filling of the voids between the PS spheres), which is restricted to
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A simple one-pot synthesis of well-defined PS-silazane nano-composites (polystyrene, PS) is described. In contrast to the, thus far, used two-step procedure ((1) assembly of a PS template bed and (2) careful filling of the voids between the PS spheres), which is restricted to macro structuring, we are able to simply mix the PS template and a commercially available silazane precursor HTT-1800 in toluene. The key is the alteration of the zeta potential of the PS template leading to a homogeneous dispersion in the silazane-toluene mixture. Removal of solvent gives rise to a highly ordered PS-silazane nano-composites and subsequent pyrolysis leads to mesoporous silicon carbonitride (SiCN) materials. The one-pot procedure has two advantages: easy upscaling and the use of PS spheres smaller than 100 nm in diameter, here 60 nm. The PS template was characterized by photon correlation spectroscopy, zeta potential measurements, scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA). The resulting mesoporous SiCN materials were analyzed by SEM, transmission electron microscopy (TEM), nitrogen sorption analysis, and Fourier transform infrared measurements (FT-IR). Full article
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Open AccessArticle Gene Expression, Protein Function and Pathways of Arabidopsis thaliana Responding to Silver Nanoparticles in Comparison to Silver Ions, Cold, Salt, Drought, and Heat
Nanomaterials 2015, 5(2), 436-467; doi:10.3390/nano5020436
Received: 25 February 2015 / Revised: 18 March 2015 / Accepted: 23 March 2015 / Published: 27 March 2015
Cited by 9 | PDF Full-text (1702 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Silver nanoparticles (AgNPs) have been widely used in industry due to their unique physical and chemical properties. However, AgNPs have caused environmental concerns. To understand the risks of AgNPs, Arabidopsis microarray data for AgNP, Ag+, cold, salt, heat and drought stresses
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Silver nanoparticles (AgNPs) have been widely used in industry due to their unique physical and chemical properties. However, AgNPs have caused environmental concerns. To understand the risks of AgNPs, Arabidopsis microarray data for AgNP, Ag+, cold, salt, heat and drought stresses were analyzed. Up- and down-regulated genes of more than two-fold expression change were compared, while the encoded proteins of shared and unique genes between stresses were subjected to differential enrichment analyses. AgNPs affected the fewest genes (575) in the Arabidopsis genome, followed by Ag+ (1010), heat (1374), drought (1435), salt (4133) and cold (6536). More genes were up-regulated than down-regulated in AgNPs and Ag+ (438 and 780, respectively) while cold down-regulated the most genes (4022). Responses to AgNPs were more similar to those of Ag+ (464 shared genes), cold (202), and salt (163) than to drought (50) or heat (30); the genes in the first four stresses were enriched with 32 PFAM domains and 44 InterPro protein classes. Moreover, 111 genes were unique in AgNPs and they were enriched in three biological functions: response to fungal infection, anion transport, and cell wall/plasma membrane related. Despite shared similarity to Ag+, cold and salt stresses, AgNPs are a new stressor to Arabidopsis. Full article
(This article belongs to the Special Issue Advancements in Nanotoxicology)
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Open AccessArticle Band Structure Simulations of the Photoinduced Changes in the MgB2:Cr Films
Nanomaterials 2015, 5(2), 541-553; doi:10.3390/nano5020541
Received: 16 January 2015 / Revised: 25 March 2015 / Accepted: 26 March 2015 / Published: 2 April 2015
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Abstract
An approach for description of the photoinduced nonlinear optical effects in the superconducting MgB2:Cr2O3 nanocrystalline film is proposed. It includes the molecular dynamics step-by-step optimization of the two separate crystalline phases. The principal role for the photoinduced nonlinear
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An approach for description of the photoinduced nonlinear optical effects in the superconducting MgB2:Cr2O3 nanocrystalline film is proposed. It includes the molecular dynamics step-by-step optimization of the two separate crystalline phases. The principal role for the photoinduced nonlinear optical properties plays nanointerface between the two phases. The first modified layers possess a form of slightly modified perfect crystalline structure. The next layer is added to the perfect crystalline structure and the iteration procedure is repeated for the next layer. The total energy here is considered as a varied parameter. To avoid potential jumps on the borders we have carried out additional derivative procedure. Full article
(This article belongs to the Special Issue Nanophotonic Materials)
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Open AccessArticle Synthesis and Adsorption Property of SiO2@Co(OH)2 Core-Shell Nanoparticles
Nanomaterials 2015, 5(2), 554-564; doi:10.3390/nano5020554
Received: 10 February 2015 / Revised: 17 March 2015 / Accepted: 19 March 2015 / Published: 3 April 2015
Cited by 2 | PDF Full-text (3274 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Silica nanoparticles were directly coated with cobalt hydroxide by homogeneous precipitation of slowly decomposing urea in cobalt nitrate solution. The cobalt hydroxide was amorphous, and its morphology was nanoflower-like. The BET (Brunauer-Emmett-Teller) surface area of the core-shell composite was 221 m2/g.
[...] Read more.
Silica nanoparticles were directly coated with cobalt hydroxide by homogeneous precipitation of slowly decomposing urea in cobalt nitrate solution. The cobalt hydroxide was amorphous, and its morphology was nanoflower-like. The BET (Brunauer-Emmett-Teller) surface area of the core-shell composite was 221 m2/g. Moreover, the possible formation procedure is proposed: the electropositive cobalt ions were first adsorbed on the electronegative silica nanoparticles surface, which hydrolyzed to form cobalt hydroxide nanoparticles. Then, the cobalt hydroxide nanoparticles were aggregated to form nanoflakes. Finally, the nanoflakes self-assembled, forming cobalt hydroxide nanoflowers. Adsorption measurement showed that the core-shell composite exhibited excellent adsorption capability of Rhodamine B (RB). Full article
(This article belongs to the Special Issue Nanomaterials for Energy and Sustainability Applications)
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Open AccessArticle Metal Organic Framework Micro/Nanopillars of Cu(BTC)·3H2O and Zn(ADC)·DMSO
Nanomaterials 2015, 5(2), 565-576; doi:10.3390/nano5020565
Received: 3 March 2015 / Revised: 26 March 2015 / Accepted: 30 March 2015 / Published: 9 April 2015
Cited by 6 | PDF Full-text (1250 KB) | HTML Full-text | XML Full-text
Abstract
In this work, we report the optical and thermal properties of Cu(BTC)·3H2O (BTC = 1,3,5-benzenetricarboxylic acid) and Zn(ADC)·DMSO (ADC = 9,10- anthracenedicarboxylic acid, DMSO = dimethyl sulfoxide) metal-organic frameworks (MOFs) micro/nanopillars. The morphologies of MOFs on surfaces are most in the
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In this work, we report the optical and thermal properties of Cu(BTC)·3H2O (BTC = 1,3,5-benzenetricarboxylic acid) and Zn(ADC)·DMSO (ADC = 9,10- anthracenedicarboxylic acid, DMSO = dimethyl sulfoxide) metal-organic frameworks (MOFs) micro/nanopillars. The morphologies of MOFs on surfaces are most in the form of micro/nanopillars that were vertically oriented on the surface. The size and morphology of the pillars depend on the evaporation time, concentration, solvent, substrate, and starting volume of solutions. The crystal structures of the nanopillars and micropillars are the same, confirmed by powder XRD. Zn(ADC)·DMSO pillars have a strong blue fluorescence. Most of ADC in the pillars are in the form of monomers, which is different from ADC in the solid powder. Full article
(This article belongs to the Special Issue Nanomaterials for Energy and Sustainability Applications)
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Open AccessArticle Titration of DNA/Carbon Nanotube Complexes with Double-Chained Oppositely Charged Surfactants
Nanomaterials 2015, 5(2), 722-736; doi:10.3390/nano5020722
Received: 22 January 2015 / Revised: 26 March 2015 / Accepted: 10 April 2015 / Published: 30 April 2015
Cited by 3 | PDF Full-text (2011 KB) | HTML Full-text | XML Full-text
Abstract
1/1 dispersions of ss-DNA/CNT complexes in mass ratios were investigated in a mixture with didodecyldimethylammonium bromide, DDAB. Depending on the amounts of the surface-active agent and of the complexes, solutions, precipitates, or re-dissolution occur. DDAB titrates the phosphate groups on the outer surface
[...] Read more.
1/1 dispersions of ss-DNA/CNT complexes in mass ratios were investigated in a mixture with didodecyldimethylammonium bromide, DDAB. Depending on the amounts of the surface-active agent and of the complexes, solutions, precipitates, or re-dissolution occur. DDAB titrates the phosphate groups on the outer surface of the complex and controls the phase sequence in these systems. The combination of different experimental methods determined the phases that occur therein. The results are based on optical absorbance, Dynamic Light Scattering, ionic conductivity, ζ-potential, optical microscopy and AFM. From the above findings a (pseudo)-binary phase diagram is attained. The system has strong similarities with polymer-surfactant mixtures. In fact, its properties conform to cases in which interactions between rigid rod-like polyelectrolytes and oppositely charged species take place. The peculiarities of double-chained DDAB in the process imply significant differences with respect to the behavior of single chain surfactants. In fact, DDAB associates into vesicular entities, when the homologous single chain species forms small micellar aggregates. Full article
(This article belongs to the Special Issue Frontiers in Nucleic Acid Nanotechnology)
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Open AccessArticle Synthesis, Characterization and Gas Sensing Properties of Ag@α-Fe2O3 Core–Shell Nanocomposites
Nanomaterials 2015, 5(2), 737-749; doi:10.3390/nano5020737
Received: 25 March 2015 / Revised: 20 April 2015 / Accepted: 29 April 2015 / Published: 5 May 2015
Cited by 16 | PDF Full-text (2723 KB) | HTML Full-text | XML Full-text
Abstract
Ag@α-Fe2O3 nanocomposite having a core–shell structure was synthesized by a two-step reduction-sol gel approach, including Ag nanoparticles synthesis by sodium borohydride as the reducing agent in a first step and the subsequent mixing with a Fe+3 sol for α-Fe
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Ag@α-Fe2O3 nanocomposite having a core–shell structure was synthesized by a two-step reduction-sol gel approach, including Ag nanoparticles synthesis by sodium borohydride as the reducing agent in a first step and the subsequent mixing with a Fe+3 sol for α-Fe2O3 coating. The synthesized Ag@α-Fe2O3 nanocomposite has been characterized by various techniques, such as SEM, TEM and UV-Vis spectroscopy. The electrical and gas sensing properties of the synthesized composite towards low concentrations of ethanol have been evaluated. The Ag@α-Fe2O3 nanocomposite showed better sensing characteristics than the pure α-Fe2O3. The peculiar hierarchical nano-architecture and the chemical and electronic sensitization effect of Ag nanoparticles in Ag@α-Fe2O3 sensors were postulated to play a key role in modulating gas-sensing properties in comparison to pristine α-Fe2O3 sensors. Full article
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Open AccessArticle Modeling the Dispersibility of Single Walled Carbon Nanotubes in Organic Solvents by Quantitative Structure-Activity Relationship Approach
Nanomaterials 2015, 5(2), 778-791; doi:10.3390/nano5020778
Received: 12 February 2015 / Revised: 29 April 2015 / Accepted: 4 May 2015 / Published: 12 May 2015
Cited by 5 | PDF Full-text (374 KB) | HTML Full-text | XML Full-text
Abstract
The knowledge of physico-chemical properties of carbon nanotubes, including behavior in organic solvents is very important for design, manufacturing and utilizing of their counterparts with improved properties. In the present study a quantitative structure-activity/property relationship (QSAR/QSPR) approach was applied to predict the dispersibility
[...] Read more.
The knowledge of physico-chemical properties of carbon nanotubes, including behavior in organic solvents is very important for design, manufacturing and utilizing of their counterparts with improved properties. In the present study a quantitative structure-activity/property relationship (QSAR/QSPR) approach was applied to predict the dispersibility of single walled carbon nanotubes (SWNTs) in various organic solvents. A number of additive descriptors and quantum-chemical descriptors were calculated and utilized to build QSAR models. The best predictability is shown by a 4-variable model. The model showed statistically good results (R2training = 0.797, Q2 = 0.665, R2test = 0.807), with high internal and external correlation coefficients. Presence of the X0Av descriptor and its negative term suggest that small size solvents have better SWCNTs solubility. Mass weighted descriptor ATS6m also indicates that heavier solvents (and small in size) most probably are better solvents for SWCNTs. The presence of the Dipole Z descriptor indicates that higher polarizability of the solvent molecule increases the solubility. The developed model and contributed descriptors can help to understand the mechanism of the dispersion process and predictorganic solvents that improve the dispersibility of SWNTs. Full article
(This article belongs to the Special Issue Advancements in Nanotoxicology)
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Open AccessArticle Thermo-Optical Properties of Thin-Film TiO2–Al2O3 Bilayers Fabricated by Atomic Layer Deposition
Nanomaterials 2015, 5(2), 792-803; doi:10.3390/nano5020792
Received: 28 February 2015 / Revised: 10 May 2015 / Accepted: 13 May 2015 / Published: 18 May 2015
Cited by 4 | PDF Full-text (2430 KB) | HTML Full-text | XML Full-text
Abstract
We investigate the optical and thermo-optical properties of amorphous TiO\(_2\)–Al\(_2\)O\(_3\) thin-film bilayers fabricated by atomic layer deposition (ALD). Seven samples of TiO\(_2\)–Al\(_2\)O\(_3\) bilayers are fabricated by growing Al\(_2\)O\(_3\) films of different thicknesses on the surface of TiO\(_2\) films of constant thickness (100 nm).
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We investigate the optical and thermo-optical properties of amorphous TiO\(_2\)–Al\(_2\)O\(_3\) thin-film bilayers fabricated by atomic layer deposition (ALD). Seven samples of TiO\(_2\)–Al\(_2\)O\(_3\) bilayers are fabricated by growing Al\(_2\)O\(_3\) films of different thicknesses on the surface of TiO\(_2\) films of constant thickness (100 nm). Temperature-induced changes in the optical refractive indices of these thin-film bilayers are measured by a variable angle spectroscopic ellipsometer VASE\textsuperscript{\textregistered}. The optical data and the thermo-optic coefficients of the films are retrieved and calculated by applying the Cauchy model and the linear fitting regression algorithm, in order to evaluate the surface porosity model of TiO\(_2\) films. The effects of TiO\(_2\) surface defects on the films' thermo-optic properties are reduced and modified by depositing ultra-thin ALD-Al\(_2\)O\(_3\) diffusion barrier layers. Increasing the ALD-Al\(_2\)O\(_3\) thickness from 20 nm to 30 nm results in a sign change of the thermo-optic coefficient of the ALD-TiO\(_2\). The thermo-optic coefficients of the 100 nm-thick ALD-TiO\(_2\) film and 30 nm-thick ALD-Al\(_2\)O\(_3\) film in a bilayer are (0.048 \(\pm\) 0.134) \(\times 10 ^{-4} {^\circ}\mathrm {C}^{-1}\) and (0.680 \(\pm\) 0.313) \(\times 10^{-4} {^\circ} \mathrm {C}^{-1}\), respectively, at a temperature \(T = 62 ^\circ \mathrm{C}\). Full article
(This article belongs to the Special Issue Nanophotonic Materials)
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Open AccessArticle Phosphorothioate DNA Stabilized Fluorescent Gold and Silver Nanoclusters
Nanomaterials 2015, 5(2), 804-813; doi:10.3390/nano5020804
Received: 30 March 2015 / Accepted: 7 May 2015 / Published: 19 May 2015
Cited by 5 | PDF Full-text (1448 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Unmodified single-stranded DNA has recently gained popularity for the templated synthesis of fluorescent noble metal nanoclusters (NCs). Bright, stable, and biocompatible clusters have been developed primarily through optimization of DNA sequence. However, DNA backbone modifications have not yet been investigated. In this work,
[...] Read more.
Unmodified single-stranded DNA has recently gained popularity for the templated synthesis of fluorescent noble metal nanoclusters (NCs). Bright, stable, and biocompatible clusters have been developed primarily through optimization of DNA sequence. However, DNA backbone modifications have not yet been investigated. In this work, phosphorothioate (PS) DNAs are evaluated in the synthesis of Au and Ag nanoclusters, and are employed to successfully template a novel emitter using T15 DNA at neutral pH. Mechanistic studies indicate a distinct UV-dependent formation mechanism that does not occur through the previously reported thymine N3. The positions of PS substitution have been optimized. This is the first reported use of a T15 template at physiological pH for AgNCs. Full article
(This article belongs to the Special Issue Frontiers in Nucleic Acid Nanotechnology)
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Open AccessArticle Thermal Emission Control via Bandgap Engineering in Aperiodically Designed Nanophotonic Devices
Nanomaterials 2015, 5(2), 814-825; doi:10.3390/nano5020814
Received: 22 April 2015 / Revised: 8 May 2015 / Accepted: 13 May 2015 / Published: 20 May 2015
Cited by 2 | PDF Full-text (506 KB) | HTML Full-text | XML Full-text
Abstract
Aperiodic photonic crystals can open up novel routes for more efficient photon management due to increased degrees of freedom in their design along with the unique properties brought about by the long-range aperiodic order as compared to their periodic counterparts. In this work
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Aperiodic photonic crystals can open up novel routes for more efficient photon management due to increased degrees of freedom in their design along with the unique properties brought about by the long-range aperiodic order as compared to their periodic counterparts. In this work we first describe the fundamental notions underlying the idea of thermal emission/absorption control on the basis of the systematic use of aperiodic multilayer designs in photonic quasicrystals. Then, we illustrate the potential applications of this approach in order to enhance the performance of daytime radiative coolers and solar thermoelectric energy generators. Full article
(This article belongs to the Special Issue Nanomaterials for Energy and Sustainability Applications)
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Open AccessArticle Graphene Oxide Synthesis from Agro Waste
Nanomaterials 2015, 5(2), 826-834; doi:10.3390/nano5020826
Received: 6 April 2015 / Revised: 9 May 2015 / Accepted: 12 May 2015 / Published: 20 May 2015
Cited by 15 | PDF Full-text (473 KB) | HTML Full-text | XML Full-text
Abstract
A new method of graphene oxide (GO) synthesis via single-step reforming of sugarcane bagasse agricultural waste by oxidation under muffled atmosphere conditions is reported. The strong and sharp X-ray diffraction peak at 2θ = 11.6° corresponds to an interlayer distance of 0.788 nm
[...] Read more.
A new method of graphene oxide (GO) synthesis via single-step reforming of sugarcane bagasse agricultural waste by oxidation under muffled atmosphere conditions is reported. The strong and sharp X-ray diffraction peak at 2θ = 11.6° corresponds to an interlayer distance of 0.788 nm (d002) for the AB stacked GOs. High-resolution transmission electron microscopy (HRTEM) and selected-area electron diffraction (SAED) confirm the formation of the GO layer structure and the hexagonal framework. This is a promising method for fast and effective synthesis of GO from sugarcane bagasse intended for a variety of energy and environmental applications. Full article
(This article belongs to the Special Issue Nanomaterials for Energy and Sustainability Applications)
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Open AccessArticle Toxicity and Biokinetics of Colloidal Gold Nanoparticles
Nanomaterials 2015, 5(2), 835-850; doi:10.3390/nano5020835
Received: 9 April 2015 / Revised: 7 May 2015 / Accepted: 13 May 2015 / Published: 21 May 2015
Cited by 11 | PDF Full-text (1420 KB) | HTML Full-text | XML Full-text
Abstract
Gold nanoparticles (Au-NPs) have promising potential for diverse biological application, but it has not been completely determined whether Au-NP has potential toxicity in vitro and in vivo. In the present study, toxicity of Au-NP was evaluated in human intestinal cells as well
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Gold nanoparticles (Au-NPs) have promising potential for diverse biological application, but it has not been completely determined whether Au-NP has potential toxicity in vitro and in vivo. In the present study, toxicity of Au-NP was evaluated in human intestinal cells as well as in rats after 14-day repeated oral administration. Biokinetic study was also performed to assess oral absorption and tissue distribution. The results demonstrated that Au-NP did not cause cytotoxic effects on cells after 24 h exposure in terms of inhibition of cell proliferation, membrane damage, and oxidative stress. However, when a small number of cells were exposed to Au-NP for seven days, colony forming ability remarkably decreased by Au-NP treatment, suggesting its potential toxicity after long-term exposure at high concentration. Biokinetic study revealed that Au-NP slowly entered the blood stream and slightly accumulated only in kidney after oral administration to rats. Whereas, orally administered Au ions were rapidly absorbed, and then distributed in kidney, liver, lung, and spleen at high levels, suggesting that the biological fate of Au-NP is primarily in nanoparticulate form, not in ionic Au. Fourteen-day repeated oral toxicity evaluation showed that Au-NP did not cause severe toxicity in rats based on histopathological, hematological, and serum biochemical analysis. Full article
(This article belongs to the Special Issue Advancements in Nanotoxicology)
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Open AccessCommunication Targeting of Apoptotic Cells Using Functionalized Fe2O3 Nanoparticles
Nanomaterials 2015, 5(2), 874-884; doi:10.3390/nano5020874
Received: 29 March 2015 / Accepted: 20 May 2015 / Published: 26 May 2015
Cited by 1 | PDF Full-text (2891 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Fe2O3 nanoparticles (NPs) have been synthesized and functionalized with SiO2 and -NH2 group, respectively. Conjugation to fluorescently-labeled poly-caspase inhibitor (SR-FLIVO) has been carried out for better cellular uptake studies of apoptosis arising from brain focal cerebral ischemia. Highest
[...] Read more.
Fe2O3 nanoparticles (NPs) have been synthesized and functionalized with SiO2 and -NH2 group, respectively. Conjugation to fluorescently-labeled poly-caspase inhibitor (SR-FLIVO) has been carried out for better cellular uptake studies of apoptosis arising from brain focal cerebral ischemia. Highest conjugation affinity to SR-FLIVO was found to be ca. 80% for Fe2O3-SiO-NH2 functionalized nanoparticles (FNPs). Tracking of SR-FLIVO conjugated functionalized nanoparticles (SR-FLIVO-FNPs) in vivo and in vitro has been carried out and detected using microscopic techniques after histochemical staining methods. Experimental results revealed that SR-FLIVO-FNPs probe could passively cross the blood brain barrier (BBB) and accumulated within the apoptotic cell. Optimization of SR-FLIVO-FNPs probe can effectively promise to open a new era for intracellular drug delivery and brain diagnosis. Full article
(This article belongs to the Special Issue Nanoparticles in Theranostics)
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Open AccessArticle Electronic Structure and Magnetism of Mn-Doped ZnO Nanowires
Nanomaterials 2015, 5(2), 885-894; doi:10.3390/nano5020885
Received: 10 April 2015 / Revised: 4 May 2015 / Accepted: 21 May 2015 / Published: 27 May 2015
Cited by 5 | PDF Full-text (1009 KB) | HTML Full-text | XML Full-text
Abstract
The geometric structures, electronic and magnetic properties of Mn-doped ZnO nanowires were investigated using density functional theory. The results indicated that all the calculated energy differences were negative, and the energy of the ground state was 0.229 eV lower than ferromagnetic coupling, which
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The geometric structures, electronic and magnetic properties of Mn-doped ZnO nanowires were investigated using density functional theory. The results indicated that all the calculated energy differences were negative, and the energy of the ground state was 0.229 eV lower than ferromagnetic coupling, which show higher stability in antiferromagnetic coupling. The calculated results indicated that obvious spin splitting phenomenon occurred near the Femi level. The Zn atoms on the inner layer of ZnO nanowires are easily substituted by Mn atoms along the [0001] direction. It was also shown that the Mn2+-O2−-Mn2+ magnetic coupling formed by intermediate O atom was proved to be caused by orbital hybridization between Mn 3d and O 2p states. The magnetic moments were mainly attributed to the unpaired Mn 3d orbitals, but not relevant with doping position of Mn atoms. Moreover, the optical properties of Mn-doped ZnO nanowires exhibited a novel blue-shifted optical absorption and enhanced ultraviolet-light emission. The above results show that the Mn-doped ZnO nanowires are a new type of magneto-optical materials with great promise. Full article
(This article belongs to the Special Issue Nanophotonic Materials)
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Open AccessArticle Emission Properties of Fluorescent Nanoparticles Determined by Their Optical Environment
Nanomaterials 2015, 5(2), 895-905; doi:10.3390/nano5020895
Received: 20 April 2015 / Revised: 11 May 2015 / Accepted: 25 May 2015 / Published: 29 May 2015
Cited by 2 | PDF Full-text (1084 KB) | HTML Full-text | XML Full-text
Abstract
The emission rate of a radiating dipole within a nanoparticle is crucially dependent on its surrounding refractive index environment. In this manuscript, we present numerical results on how the emission rates are affected for nanoparticles in a homogenous and substrate environment. These results
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The emission rate of a radiating dipole within a nanoparticle is crucially dependent on its surrounding refractive index environment. In this manuscript, we present numerical results on how the emission rates are affected for nanoparticles in a homogenous and substrate environment. These results are general, applicable to any refractive index distribution and emitter. Full article
(This article belongs to the Special Issue Nanophotonic Materials)
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Open AccessArticle Kinetic Uptake Studies of Powdered Materials in Solution
Nanomaterials 2015, 5(2), 969-980; doi:10.3390/nano5020969
Received: 10 April 2015 / Accepted: 27 May 2015 / Published: 4 June 2015
Cited by 10 | PDF Full-text (500 KB) | HTML Full-text | XML Full-text
Abstract
Challenges exist for the study of time dependent sorption processes for heterogeneous systems, especially in the case of dispersed nanomaterials in solvents or solutions because they are not well suited to conventional batch kinetic experiments. In this study, a comparison of batch versus
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Challenges exist for the study of time dependent sorption processes for heterogeneous systems, especially in the case of dispersed nanomaterials in solvents or solutions because they are not well suited to conventional batch kinetic experiments. In this study, a comparison of batch versus a one-pot setup in two variable configurations was evaluated for the study of uptake kinetics in heterogeneous (solid/solution) systems: (i) conventional batch method; (ii) one-pot system with dispersed adsorbent in solution with a semi-permeable barrier (filter paper or dialysis tubing) for in situ sampling; and (iii) one-pot system with an adsorbent confined in a semi-permeable barrier (dialysis tubing or filter paper barrier) with ex situ sampling. The sorbent systems evaluated herein include several cyclodextrin-based polyurethane materials with two types of phenolic dyes: p-nitrophenol and phenolphthalein. The one-pot kinetics method with in situ (Method ii) or ex situ (Method iii) sampling described herein offers significant advantages for the study of heterogeneous sorption kinetics of highly dispersed sorbent materials with particles sizes across a range of dimensions from the micron to nanometer scale. The method described herein will contribute positively to the development of advanced studies for heterogeneous sorption processes where an assessment of the relative uptake properties is required at different experimental conditions. The results of this study will be advantageous for the study of nanomaterials with significant benefits over batch kinetic studies for a wide range of heterogeneous sorption processes. Full article
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Open AccessArticle Plasmonics Meets Biology through Optics
Nanomaterials 2015, 5(2), 1022-1033; doi:10.3390/nano5021022
Received: 17 April 2015 / Revised: 29 May 2015 / Accepted: 2 June 2015 / Published: 9 June 2015
Cited by 1 | PDF Full-text (1449 KB) | HTML Full-text | XML Full-text
Abstract
Plasmonic metallic nanoparticles (NPs) represent a relevant class of nanomaterials, which is able to achieve light localization down to nanoscale by exploiting a phenomenon called Localized Plasmon Resonance. In the last few years, NPs have been proposed to trigger DNA release or enhance
[...] Read more.
Plasmonic metallic nanoparticles (NPs) represent a relevant class of nanomaterials, which is able to achieve light localization down to nanoscale by exploiting a phenomenon called Localized Plasmon Resonance. In the last few years, NPs have been proposed to trigger DNA release or enhance ablation of diseased tissues, while minimizing damage to healthy tissues. In view of the therapeutic relevance of such plasmonic NPs; a detailed characterization of the electrostatic interaction between positively charged gold nanorods (GNRs) and a negatively charged whole-genome DNA solution is reported. The preparation of the hybrid biosystem has been investigated as a function of DNA concentration by means of ζ-potential; hydrodynamic diameter and gel electrophoresis analysis. The results have pointed out the specific conditions to achieve the most promising GNRs/DNA complex and its photo-thermal properties have been investigated. The overall study allows to envisage the possibility to ingeniously combine plasmonic and biological materials and, thus, enable design and development of an original non invasive all-optical methodology for monitoring photo-induced temperature variation with high sensitivity. Full article
(This article belongs to the Special Issue Nanophotonic Materials)
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Open AccessArticle Crosslinked Carbon Nanotubes/Polyaniline Composites as a Pseudocapacitive Material with High Cycling Stability
Nanomaterials 2015, 5(2), 1034-1047; doi:10.3390/nano5021034
Received: 28 April 2015 / Revised: 15 May 2015 / Accepted: 3 June 2015 / Published: 11 June 2015
Cited by 11 | PDF Full-text (1837 KB) | HTML Full-text | XML Full-text
Abstract
The poor cycling stability of polyaniline (PANI) limits its practical application as a pseudocapacitive material due to the volume change during the charge-discharge procedure. Herein, crosslinked carbon nanotubes/polyaniline (C-CNTs/PANI) composites had been designed by the in situ chemical oxidative polymerization of aniline in
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The poor cycling stability of polyaniline (PANI) limits its practical application as a pseudocapacitive material due to the volume change during the charge-discharge procedure. Herein, crosslinked carbon nanotubes/polyaniline (C-CNTs/PANI) composites had been designed by the in situ chemical oxidative polymerization of aniline in the presence of crosslinked carbon nanotubes (C-CNTs), which were obtained by coupling of the functionalized carbon nanotubes with 1,4-benzoquinone. The composite showed a specific capacitance of 294 F/g at the scan rate of 10 mV/s, and could retain 95% of its initial specific capacitance after 1000 CV cycles. Such high electrochemical cycling stability resulting from the crosslinked skeleton of the C-CNTs makes them potential electrode materials for a supercapacitor. Full article
(This article belongs to the Special Issue Nanomaterials for Energy and Sustainability Applications)
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Open AccessArticle Examination of Single-Walled Carbon Nanotubes Uptake and Toxicity from Dietary Exposure: Tracking Movement and Impacts in the Gastrointestinal System
Nanomaterials 2015, 5(2), 1066-1086; doi:10.3390/nano5021066
Received: 5 May 2015 / Accepted: 3 June 2015 / Published: 12 June 2015
Cited by 9 | PDF Full-text (3933 KB) | HTML Full-text | XML Full-text
Abstract
Previous studies indicate that exposure of fish to pristine single-walled carbon nanotubes (SWCNTs) by oral gavage, causes no overt toxicity, and no appreciable absorption has been observed. However, in the environment, SWCNTs are likely to be present in dietary sources, which may result
[...] Read more.
Previous studies indicate that exposure of fish to pristine single-walled carbon nanotubes (SWCNTs) by oral gavage, causes no overt toxicity, and no appreciable absorption has been observed. However, in the environment, SWCNTs are likely to be present in dietary sources, which may result in differential impacts on uptake and biological effects. Additionally, the potential of these materials to sorb nutrients (proteins, carbohydrates, and lipids) while present in the gastrointestinal (GI) tract may lead to nutrient depletion conditions that impact processes such as growth and reproduction. To test this phenomenon, fathead minnows were fed a commercial diet either with or without SWCNTs for 96 h. Tracking and quantification of SWCNTs using near-infrared fluorescence (NIRF) imaging during feeding studies showed the presence of food does not facilitate transport of SWCNTs across the intestinal epithelia. Targeting genes shown to be responsive to nutrient depletion (peptide transporters, peptide hormones, and lipases) indicated that pept2, a peptide transporter, and cck, a peptide hormone, showed differential mRNA expression by 96 h, a response that may be indicative of nutrient limitation. The results of the current study increase our understanding of the movement of SWCNTs through the GI tract, while the changes in nutrient processing genes highlight a novel mechanism of sublethal toxicity in aquatic organisms. Full article
(This article belongs to the Special Issue Advancements in Nanotoxicology)
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Open AccessArticle Hybrid Mesoporous Silicas and Microporous POSS-Based Frameworks Incorporating Evaporation-Induced Self-Assembly
Nanomaterials 2015, 5(2), 1087-1101; doi:10.3390/nano5021087
Received: 8 May 2015 / Accepted: 11 June 2015 / Published: 16 June 2015
Cited by 2 | PDF Full-text (6567 KB) | HTML Full-text | XML Full-text
Abstract
We fabricated a series of mesoporous silicas and mesoporous organosilicates with hierarchical porosity through evaporation-induced self-assembly using Pluronic F127 as a template in this study. We could tailor the mesophase of each mesoporous silica sample by varying the weight ratio of its two
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We fabricated a series of mesoporous silicas and mesoporous organosilicates with hierarchical porosity through evaporation-induced self-assembly using Pluronic F127 as a template in this study. We could tailor the mesophase of each mesoporous silica sample by varying the weight ratio of its two silica sources: tetraethyl orthosilicate (TEOS) and triethoxysilane hydrosilylated octavinyl polyhedral oligomeric silsesquioxane (OV-POSS-SILY). The mesophases ranged from an ordered body-centered cubic (bcc) structure (TEOS alone) to ordered face-centered cubic (fcc) structure (10 and 20 wt.% of OV-POSS-SILY) and finally to disordered spherical pores (≥30 wt.% of OV-POSS-SILY). We used small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) to study the transformations of these mesophases, while N2 isotherm sorption curves revealed the porosities of these mesoporous silicate samples. Moreover, 29Si CP/MAS solid state nuclear magnetic resonance spectroscopy allowed us to analyze the compositions of the POSS-containing silicate frameworks. Such functional mesoporous silica samples incorporating microporous POSS building units have potential applications in various systems, including optical and electronic devices. Full article
(This article belongs to the Special Issue Frontiers in Mesoporous Nanomaterials)
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Open AccessArticle A Sustainable Approach to Fabricating Ag Nanoparticles/PVA Hybrid Nanofiber and Its Catalytic Activity
Nanomaterials 2015, 5(2), 1124-1135; doi:10.3390/nano5021124
Received: 13 May 2015 / Revised: 16 June 2015 / Accepted: 18 June 2015 / Published: 23 June 2015
Cited by 6 | PDF Full-text (5601 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Ag nanoparticles were synthesized by using Ficus altissima Blume leaf extract as a reducing agent at room temperature. The resulting Ag nanoparticles/PVA mixture was employed to create Ag nanoparticles/PVA (polyvinyl alcohol) hybrid nanofibers via an electrospinning technique. The obtained nanofibers were confirmed by
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Ag nanoparticles were synthesized by using Ficus altissima Blume leaf extract as a reducing agent at room temperature. The resulting Ag nanoparticles/PVA mixture was employed to create Ag nanoparticles/PVA (polyvinyl alcohol) hybrid nanofibers via an electrospinning technique. The obtained nanofibers were confirmed by means of UV-Vis spectroscopy, The X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and then tested to catalyze KBH4 reduction of methylene blue (MB). The catalytic results demonstrate that the MB can be reduced completely within 15 min. In addition, the Ag nanoparticles/PVA hybrid nanofibers show reusability for three cycles with no obvious losses in degradation ratio of the MB. Full article
(This article belongs to the Special Issue Nanomaterials for Energy and Sustainability Applications)
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Open AccessReview Ceramic Nanocomposites from Tailor-Made Preceramic Polymers
Nanomaterials 2015, 5(2), 468-540; doi:10.3390/nano5020468
Received: 24 February 2015 / Revised: 13 March 2015 / Accepted: 15 March 2015 / Published: 1 April 2015
Cited by 24 | PDF Full-text (2176 KB) | HTML Full-text | XML Full-text
Abstract
The present Review addresses current developments related to polymer-derived ceramic nanocomposites (PDC-NCs). Different classes of preceramic polymers are briefly introduced and their conversion into ceramic materials with adjustable phase compositions and microstructures is presented. Emphasis is set on discussing the intimate relationship between
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The present Review addresses current developments related to polymer-derived ceramic nanocomposites (PDC-NCs). Different classes of preceramic polymers are briefly introduced and their conversion into ceramic materials with adjustable phase compositions and microstructures is presented. Emphasis is set on discussing the intimate relationship between the chemistry and structural architecture of the precursor and the structural features and properties of the resulting ceramic nanocomposites. Various structural and functional properties of silicon-containing ceramic nanocomposites as well as different preparative strategies to achieve nano-scaled PDC-NC-based ordered structures are highlighted, based on selected ceramic nanocomposite systems. Furthermore, prospective applications of the PDC-NCs such as high-temperature stable materials for thermal protection systems, membranes for hot gas separation purposes, materials for heterogeneous catalysis, nano-confinement materials for hydrogen storage applications as well as anode materials for secondary ion batteries are introduced and discussed in detail. Full article
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Open AccessReview Magneto-Plasmonics and Resonant Interaction of Light with Dynamic Magnetisation in Metallic and All-Magneto-Dielectric Nanostructures
Nanomaterials 2015, 5(2), 577-613; doi:10.3390/nano5020577
Received: 24 February 2015 / Revised: 23 March 2015 / Accepted: 27 March 2015 / Published: 9 April 2015
Cited by 16 | PDF Full-text (1992 KB) | HTML Full-text | XML Full-text
Abstract
A significant interest in combining plasmonics and magnetism at the nanoscale gains momentum in both photonics and magnetism sectors that are concerned with the resonant enhancement of light-magnetic-matter interaction in nanostructures. These efforts result in a considerable amount of literature, which is difficult
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A significant interest in combining plasmonics and magnetism at the nanoscale gains momentum in both photonics and magnetism sectors that are concerned with the resonant enhancement of light-magnetic-matter interaction in nanostructures. These efforts result in a considerable amount of literature, which is difficult to collect and digest in limited time. Furthermore, there is insufficient exchange of results between the two research sectors. Consequently, the goal of this review paper is to bridge this gap by presenting an overview of recent progress in the field of magneto-plasmonics from two different points of view: magneto-plasmonics, and magnonics and magnetisation dynamics. It is expected that this presentation style will make this review paper of particular interest to both general physical audience and specialists conducting research on photonics, plasmonics, Brillouin light scattering spectroscopy of magnetic nanostructures and magneto-optical Kerr effect magnetometry, as well as ultrafast all-optical and THz-wave excitation of spin waves. Moreover, readers interested in a new, rapidly emerging field of all-dielectric nanophotonics will find a section about all-magneto-dielectric nanostructures. Full article
(This article belongs to the Special Issue Nanophotonic Materials)
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Open AccessReview Optical and Structural Properties of Si Nanocrystals in SiO2 Films
Nanomaterials 2015, 5(2), 614-655; doi:10.3390/nano5020614
Received: 4 March 2015 / Revised: 7 April 2015 / Accepted: 10 April 2015 / Published: 22 April 2015
Cited by 8 | PDF Full-text (4922 KB) | HTML Full-text | XML Full-text
Abstract
Optical and structural properties of Si nanocrystals (Si-nc) in silica films are described. For the SiOx (x < 2) films annealed above 1000 °C, the Raman signal of Si-nc and the absorption coefficient are proportional to the amount of elemental Si detected by
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Optical and structural properties of Si nanocrystals (Si-nc) in silica films are described. For the SiOx (x < 2) films annealed above 1000 °C, the Raman signal of Si-nc and the absorption coefficient are proportional to the amount of elemental Si detected by X-ray photoelectron spectroscopy. A good agreement is found between the measured refractive index and the value estimated by using the effective-medium approximation. The extinction coefficient of elemental Si is found to be between the values of crystalline and amorphous Si. Thermal annealing increases the degree of Si crystallization; however, the crystallization and the Si–SiO2 phase separation are not complete after annealing at 1200 °C. The 1.5-eV PL quantum yield increases as the amount of elemental Si decreases; thus, this PL is probably not directly from Si-nc responsible for absorption and detected by Raman spectroscopy. Continuous-wave laser light can produce very high temperatures in the free-standing films, which changes their structural and optical properties. For relatively large laser spots, the center of the laser-annealed area is very transparent and consists of amorphous SiO2. Large Si-nc (up to ∼300 nm in diameter) are observed in the ring around the central region. These Si-nc lead to high absorption and they are typically under compressive stress, which is connected with their formation from the liquid phase. By using strongly focused laser beams, the structural changes in the free-standing films can be made in submicron areas. Full article
(This article belongs to the Special Issue Nanophotonic Materials)
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Open AccessReview Structural Ceramic Nanocomposites: A Review of Properties and Powders’ Synthesis Methods
Nanomaterials 2015, 5(2), 656-696; doi:10.3390/nano5020656
Received: 6 March 2015 / Revised: 14 April 2015 / Accepted: 17 April 2015 / Published: 28 April 2015
Cited by 23 | PDF Full-text (3958 KB) | HTML Full-text | XML Full-text
Abstract
Ceramic nanocomposites are attracting growing interest, thanks to new processing methods enabling these materials to go from the research laboratory scale to the commercial level. Today, many different types of nanocomposite structures are proposed in the literature; however, to fully exploit their exceptional
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Ceramic nanocomposites are attracting growing interest, thanks to new processing methods enabling these materials to go from the research laboratory scale to the commercial level. Today, many different types of nanocomposite structures are proposed in the literature; however, to fully exploit their exceptional properties, a deep understanding of the materials’ behavior across length scales is necessary. In fact, knowing how the nanoscale structure influences the bulk properties enables the design of increasingly performing composite materials. A further key point is the ability of tailoring the desired nanostructured features in the sintered composites, a challenging issue requiring a careful control of all stages of manufacturing, from powder synthesis to sintering. This review is divided into four parts. In the first, classification and general issues of nanostructured ceramics are reported. The second provides basic structure–property relations, highlighting the grain-size dependence of the materials properties. The third describes the role of nanocrystalline second-phases on the mechanical properties of ordinary grain sized ceramics. Finally, the fourth part revises the mainly used synthesis routes to produce nanocomposite ceramic powders, underlining when possible the critical role of the synthesis method on the control of microstructure and properties of the sintered ceramics. Full article
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Open AccessReview Dealloying of Cu-Based Metallic Glasses in Acidic Solutions: Products and Energy Storage Applications
Nanomaterials 2015, 5(2), 697-721; doi:10.3390/nano5020697
Received: 4 February 2015 / Revised: 17 April 2015 / Accepted: 23 April 2015 / Published: 29 April 2015
Cited by 7 | PDF Full-text (5861 KB) | HTML Full-text | XML Full-text
Abstract
Dealloying, a famous ancient etching technique, was used to produce nanoporous metals decades ago. With the development of dealloying techniques and theories, various interesting dealloying products including nanoporous metals/alloys, metal oxides and composites, which exhibit excellent catalytic, optical and sensing performance, have been
[...] Read more.
Dealloying, a famous ancient etching technique, was used to produce nanoporous metals decades ago. With the development of dealloying techniques and theories, various interesting dealloying products including nanoporous metals/alloys, metal oxides and composites, which exhibit excellent catalytic, optical and sensing performance, have been developed in recent years. As a result, the research on dealloying products is of great importance for developing new materials with superior physical and chemical properties. In this paper, typical dealloying products from Cu-based metallic glasses after dealloying in hydrofluoric acid and hydrochloric acid solutions are summarized. Several potential application fields of these dealloying products are discussed. A promising application of nanoporous Cu (NPC) and NPC-contained composites related to the energy storage field is introduced. It is expected that more promising dealloying products could be developed for practical energy storage applications. Full article
(This article belongs to the Special Issue Nanomaterials for Energy and Sustainability Applications)
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Open AccessReview Multifunctional Carbon Nanostructures for Advanced Energy Storage Applications
Nanomaterials 2015, 5(2), 755-777; doi:10.3390/nano5020755
Received: 9 April 2015 / Revised: 1 May 2015 / Accepted: 5 May 2015 / Published: 8 May 2015
Cited by 23 | PDF Full-text (1788 KB) | HTML Full-text | XML Full-text
Abstract
Carbon nanostructures—including graphene, fullerenes, etc.—have found applications in a number of areas synergistically with a number of other materials. These multifunctional carbon nanostructures have recently attracted tremendous interest for energy storage applications due to their large aspect ratios, specific surface areas, and
[...] Read more.
Carbon nanostructures—including graphene, fullerenes, etc.—have found applications in a number of areas synergistically with a number of other materials. These multifunctional carbon nanostructures have recently attracted tremendous interest for energy storage applications due to their large aspect ratios, specific surface areas, and electrical conductivity. This succinct review aims to report on the recent advances in energy storage applications involving these multifunctional carbon nanostructures. The advanced design and testing of multifunctional carbon nanostructures for energy storage applications—specifically, electrochemical capacitors, lithium ion batteries, and fuel cells—are emphasized with comprehensive examples. Full article
(This article belongs to the Special Issue Nanomaterials for Energy and Sustainability Applications)
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Open AccessReview Penetration and Toxicity of Nanomaterials in Higher Plants
Nanomaterials 2015, 5(2), 851-873; doi:10.3390/nano5020851
Received: 1 April 2015 / Revised: 20 May 2015 / Accepted: 21 May 2015 / Published: 26 May 2015
Cited by 21 | PDF Full-text (365 KB) | HTML Full-text | XML Full-text
Abstract
Nanomaterials (NMs) comprise either inorganic particles consisting of metals, oxides, and salts that exist in nature and may be also produced in the laboratory, or organic particles originating only from the laboratory, having at least one dimension between 1 and 100 nm in
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Nanomaterials (NMs) comprise either inorganic particles consisting of metals, oxides, and salts that exist in nature and may be also produced in the laboratory, or organic particles originating only from the laboratory, having at least one dimension between 1 and 100 nm in size. According to shape, size, surface area, and charge, NMs have different mechanical, chemical, electrical, and optical properties that make them suitable for technological and biomedical applications and thus they are being increasingly produced and modified. Despite their beneficial potential, their use may be hazardous to health owing to the capacity to enter the animal and plant body and interact with cells. Studies on NMs involve technologists, biologists, physicists, chemists, and ecologists, so there are numerous reports that are significantly raising the level of knowledge, especially in the field of nanotechnology; however, many aspects concerning nanobiology remain undiscovered, including the interactions with plant biomolecules. In this review we examine current knowledge on the ways in which NMs penetrate plant organs and interact with cells, with the aim of shedding light on the reactivity of NMs and toxicity to plants. These points are discussed critically to adjust the balance with regard to the risk to the health of the plants as well as providing some suggestions for new studies on this topic. Full article
(This article belongs to the Special Issue Advancements in Nanotoxicology)
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Open AccessReview Nanostructured Electrode Materials for Electrochemical Capacitor Applications
Nanomaterials 2015, 5(2), 906-936; doi:10.3390/nano5020906
Received: 1 April 2015 / Accepted: 27 May 2015 / Published: 2 June 2015
Cited by 20 | PDF Full-text (2603 KB) | HTML Full-text | XML Full-text
Abstract
The advent of novel organic and inorganic nanomaterials in recent years, particularly nanostructured carbons, conducting polymers, and metal oxides, has enabled the fabrication of various energy devices with enhanced performance. In this paper, we review in detail different nanomaterials used in the fabrication
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The advent of novel organic and inorganic nanomaterials in recent years, particularly nanostructured carbons, conducting polymers, and metal oxides, has enabled the fabrication of various energy devices with enhanced performance. In this paper, we review in detail different nanomaterials used in the fabrication of electrochemical capacitor electrodes and also give a brief overview of electric double-layer capacitors, pseudocapacitors, and hybrid capacitors. From a materials point of view, the latest trends in electrochemical capacitor research are also discussed through extensive analysis of the literature and by highlighting notable research examples (published mostly since 2013). Finally, a perspective on next-generation capacitor technology is also given, including the challenges that lie ahead. Full article
(This article belongs to the Special Issue Nanomaterials for Energy and Sustainability Applications)
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Open AccessReview Synthesis of Helical Carbon Fibers and Related Materials: A Review on the Past and Recent Developments
Nanomaterials 2015, 5(2), 937-968; doi:10.3390/nano5020937
Received: 14 April 2015 / Revised: 13 May 2015 / Accepted: 15 May 2015 / Published: 2 June 2015
Cited by 1 | PDF Full-text (1252 KB) | HTML Full-text | XML Full-text
Abstract
Helical carbon fibers (HCFs) have been widely studied due to their unique helical morphology and superior properties, which make them efficient materials for several potential applications. This review summarizes the past and current advancement on the synthesis of HCFs. The review focuses and
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Helical carbon fibers (HCFs) have been widely studied due to their unique helical morphology and superior properties, which make them efficient materials for several potential applications. This review summarizes the past and current advancement on the synthesis of HCFs. The review focuses and discusses synthesis strategies and effect of experimental parameters on the growth of HCFs. The effect of preparation method of catalyst, catalyst nature, catalyst composition, catalyst size, catalyst initial and final shape, reaction temperature, reaction time, carbon source, impurities, and electromagnetic field on the growth of HCFs is reviewed. We also discuss the growth mechanism for HCFs and the synthesis of HCFs related materials. Finally, we conclude with a brief summary and an outlook on the challenges and future prospects of HCFs. Full article
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Open AccessReview Nano-Sized Cyclodextrin-Based Molecularly Imprinted Polymer Adsorbents for Perfluorinated Compounds—A Mini-Review
Nanomaterials 2015, 5(2), 981-1003; doi:10.3390/nano5020981
Received: 10 April 2015 / Revised: 14 May 2015 / Accepted: 19 May 2015 / Published: 4 June 2015
Cited by 9 | PDF Full-text (1963 KB) | HTML Full-text | XML Full-text
Abstract
Recent efforts have been directed towards the design of efficient and contaminant selective remediation technology for the removal of perfluorinated compounds (PFCs) from soils, sediments, and aquatic environments. While there is a general consensus on adsorption-based processes as the most suitable methodology for
[...] Read more.
Recent efforts have been directed towards the design of efficient and contaminant selective remediation technology for the removal of perfluorinated compounds (PFCs) from soils, sediments, and aquatic environments. While there is a general consensus on adsorption-based processes as the most suitable methodology for the removal of PFCs from aquatic environments, challenges exist regarding the optimal materials design of sorbents for selective uptake of PFCs. This article reviews the sorptive uptake of PFCs using cyclodextrin (CD)-based polymer adsorbents with nano- to micron-sized structural attributes. The relationship between synthesis of adsorbent materials and their structure relate to the overall sorption properties. Hence, the adsorptive uptake properties of CD-based molecularly imprinted polymers (CD-MIPs) are reviewed and compared with conventional MIPs. Further comparison is made with non-imprinted polymers (NIPs) that are based on cross-linking of pre-polymer units such as chitosan with epichlorohydrin in the absence of a molecular template. In general, MIPs offer the advantage of selectivity, chemical tunability, high stability and mechanical strength, ease of regeneration, and overall lower cost compared to NIPs. In particular, CD-MIPs offer the added advantage of possessing multiple binding sites with unique physicochemical properties such as tunable surface properties and morphology that may vary considerably. This mini-review provides a rationale for the design of unique polymer adsorbent materials that employ an intrinsic porogen via incorporation of a macrocyclic compound in the polymer framework to afford adsorbent materials with tunable physicochemical properties and unique nanostructure properties. Full article
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Open AccessReview Antitumor Activities of Metal Oxide Nanoparticles
Nanomaterials 2015, 5(2), 1004-1021; doi:10.3390/nano5021004
Received: 4 May 2015 / Revised: 2 June 2015 / Accepted: 4 June 2015 / Published: 9 June 2015
Cited by 27 | PDF Full-text (2364 KB) | HTML Full-text | XML Full-text
Abstract
Nanoparticles have received much attention recently due to their use in cancer therapy. Studies have shown that different metal oxide nanoparticles induce cytotoxicity in cancer cells, but not in normal cells. In some cases, such anticancer activity has been demonstrated to hold for
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Nanoparticles have received much attention recently due to their use in cancer therapy. Studies have shown that different metal oxide nanoparticles induce cytotoxicity in cancer cells, but not in normal cells. In some cases, such anticancer activity has been demonstrated to hold for the nanoparticle alone or in combination with different therapies, such as photocatalytic therapy or some anticancer drugs. Zinc oxide nanoparticles have been shown to have this activity alone or when loaded with an anticancer drug, such as doxorubicin. Other nanoparticles that show cytotoxic effects on cancer cells include cobalt oxide, iron oxide and copper oxide. The antitumor mechanism could work through the generation of reactive oxygen species or apoptosis and necrosis, among other possibilities. Here, we review the most significant antitumor results obtained with different metal oxide nanoparticles. Full article
(This article belongs to the Special Issue Advancements in Nanotoxicology)
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Open AccessReview Origin and Future of Plasmonic Optical Tweezers
Nanomaterials 2015, 5(2), 1048-1065; doi:10.3390/nano5021048
Received: 3 April 2015 / Revised: 28 May 2015 / Accepted: 4 June 2015 / Published: 12 June 2015
Cited by 8 | PDF Full-text (1357 KB) | HTML Full-text | XML Full-text
Abstract
Plasmonic optical tweezers can overcome the diffraction limits of conventional optical tweezers and enable the trapping of nanoscale objects. Extension of the trapping and manipulation of nanoscale objects with nanometer position precision opens up unprecedented opportunities for applications in the fields of biology,
[...] Read more.
Plasmonic optical tweezers can overcome the diffraction limits of conventional optical tweezers and enable the trapping of nanoscale objects. Extension of the trapping and manipulation of nanoscale objects with nanometer position precision opens up unprecedented opportunities for applications in the fields of biology, chemistry and statistical and atomic physics. Potential applications include direct molecular manipulation, lab-on-a-chip applications for viruses and vesicles and the study of nanoscale transport. This paper reviews the recent research progress and development bottlenecks and provides an overview of possible future directions in this field. Full article
(This article belongs to the Special Issue Nanophotonic Materials)
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Open AccessCommentary Dynamism of Stimuli-Responsive Nanohybrids: Environmental Implications
Nanomaterials 2015, 5(2), 1102-1123; doi:10.3390/nano5021102
Received: 30 April 2015 / Accepted: 4 June 2015 / Published: 16 June 2015
Cited by 2 | PDF Full-text (6955 KB) | HTML Full-text | XML Full-text
Abstract
Nanomaterial science and design have shifted from generating single passive nanoparticles to more complex and adaptive multi-component nanohybrids. These adaptive nanohybrids (ANHs) are designed to simultaneously perform multiple functions, while actively responding to the surrounding environment. ANHs are engineered for use as drug
[...] Read more.
Nanomaterial science and design have shifted from generating single passive nanoparticles to more complex and adaptive multi-component nanohybrids. These adaptive nanohybrids (ANHs) are designed to simultaneously perform multiple functions, while actively responding to the surrounding environment. ANHs are engineered for use as drug delivery carriers, in tissue-engineered templates and scaffolds, adaptive clothing, smart surface coatings, electrical switches and in platforms for diversified functional applications. Such ANHs are composed of carbonaceous, metallic or polymeric materials with stimuli-responsive soft-layer coatings that enable them to perform such switchable functions. Since ANHs are engineered to dynamically transform under different exposure environments, evaluating their environmental behavior will likely require new approaches. Literature on polymer science has established a knowledge core on stimuli-responsive materials. However, translation of such knowledge to environmental health and safety (EHS) of these ANHs has not yet been realized. It is critical to investigate and categorize the potential hazards of ANHs, because exposure in an unintended or shifting environment could present uncertainty in EHS. This article presents a perspective on EHS evaluation of ANHs, proposes a principle to facilitate their identification for environmental evaluation, outlines a stimuli-based classification for ANHs and discusses emerging properties and dynamic aspects for systematic EHS evaluation. Full article
(This article belongs to the Special Issue Advancements in Nanotoxicology)
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